I need to make a graphical representation of the filling of a spiral freezer. I want the operators to know the filling level at any given part of the spiral conveyor, as well as when product is expected to exit the freezer at the packaging department.
At the inlet of the freezer we have a sensor that determines the percentage width of the conveyor utilized. We do filtering and scaling (dec 0-100 %) of this value in the plc.
My first idea was to use a simple analog XY chart to represent the conveyor, and display the historical analog sensor value in this.
I have attached a picture representing this strategy.
The problem is that this will not work correctly when the freezer is stopped (historical logging keeps running), or when the freezing time (conveyor speed setpoint) is changed.
Normal freezing time (lap time of conveyor from inlet to outlet) varies between 15-60 minutes depending on the product.
Any idea how this can be realized? Should i log the data in a shift-register in the PLC? Can integer arrays be transferred from the PLC using OPC DA?